Extrafacial lentigo maligna: A progression model and enhanced diagnostic techniques using dermatoscopy and reflectance confocal microscopy.

Lentigo maligna (LM) is a subtype of lentiginous melanoma confined to the epidermis, which is associated with chronic sun exposure. Its clinical, dermatoscopic, and histopathological diagnosis can be challenging, particularly in the early and advanced stages, requiring appropriate clinicopathological correlation. This article reviews the clinical presentation, diagnosis through noninvasive methods (dermoscopy and confocal microscopy), and provides insights for diagnosis of extrafacial LM through the presentation of four representative clinical cases from different phases of a theoretical-practical progression model. Recognizing these lesions is crucial, as once they invade the dermis, they can behave like any other type of melanoma.

Dermoscopic changes in 22 extrafacial in situ and invasive lentiginous melanomas

Background: Diagnosis of non-facial melanomas on sun-damaged skin or extrafacial lentigo maligna is challenging. Objectives: To identify the evolutionary dermoscopic signs, characteristic of this type of non-facial melanoma on sun-damaged skin. Materials & Methods: This retrospective descriptive observational study included 90 dermoscopic follow-up images of 22 non-facial melanomas on sun-damaged skin from 17 high-risk melanoma patients, followed with digital dermoscopy and diagnosed between January 2016 and October 2020. We recorded dermoscopic changes by comparing each dermoscopic image with the previous one (mean dermoscopic follow-up of the excised lesions was 3.6 years). Confocal microscopy images were taken at diagnosis. Results: In total, 51.5% (95% CI: 39-64) showed an appearance or increase in featureless areas with surrounding small round or triangular dark brown-blue structures, 23% (95% CI: 23-46) showed an increase in other geometric structures (angulated lines, zig-zag lines and polycyclic structures), 5.9% (95% CI: 2-14) showed an appearance or increase in bright white lines and atypical vascularization, 26.5% (95% CI: 17-39) showed an appearance or increase in follicular pigmentation structures or follicular radial lines, and 39.7% (95% CI: 28-52) showed focal islands of pigmentation in these areas. Of the changes, 54% occurred at the last and diagnostic visit. There was an increase in size in only 20.6% (95% CI: 12-32). Also, 81.8% showed pagetoid cells in the epidermis, 95.5% atypical cells at the dermoepidermal junction by reflectance confocal microscopy, and 95.5% showed non-edged or edged and non-edged papillae. Conclusion: This study identifies the dermoscopic evolutionary changes associated with extrafacial lentigo maligna.

Nevus-associated melanoma: An observational retrospective study of 22 patients evaluated with dermoscopy and reflectance confocal microscopy.

BACKGROUND: The frequency of nevus-associated melanoma (NAM) has been estimated to be 29% of diagnosed melanomas. MATERIALS AND METHODS: This is an observational retrospective study of 22 cases of NAM diagnosed in the Universitary Hospital Alcorcón between September 2011 and 2018. The main objective was to analyze dermoscopic and RCM features of NAM. We also studied if there was an association between any dermoscopic or RCM parameter and Breslow depth. RESULTS: The most frequent dermoscopic characteristics were multicomponent pattern (50%), multifocal pigmentation (45.5%), atypical network (59.1%), and blue-gray regression structures (77.3%). RCM evidenced pagetoid cells in 95.5% melanomas (abundant in 59.1%), non-edged dermal papillae in 86.4%, atypical cells at the dermal-epidermal junction in 90.9%, and atypical junctional nesting in 81.8%. Deeper Breslow index was associated with red color (mean Breslow 0.65 vs 0.37 in melanomas without red, P = 0.035), shiny white streaks (0.85 vs 0.38, P = 0.041), abundant pagetoid cells (0.68 vs 0.26, P = 0.017), and non-edged papillae (0.59 vs 0.00, P = 0.014). CONCLUSION: RCM is a valuable tool for diagnosing NAM. Even it is very difficult to differentiate NAM from DNM both with dermoscopy and RCM, RCM can help us to detect remnants of a preexisting nevus and estimate Breslow depth.

Key dermoscopic signs in the diagnosis and progression of extrafacial lentigo maligna: Evaluation of a series of 41 cases.

BACKGROUND/OBJECTIVES: Lentigo maligna is usually located on the face. Extrafacial lentigo maligna is less common, and diagnosis of early forms is very difficult. Confocal microscopy of facial and extrafacial lentigo maligna shares the same features (abundant dendritic cells and generalised atypical junctional thickenings) and helps us to identify the dermoscopic features of extrafacial lentigo maligna. METHODS: We analysed dermoscopic and clinical features of 41 lesions diagnosed by confocal microscopy of extrafacial lentigo maligna confirmed on histology to identify dermoscopic signs of early lesions. RESULTS: Erased areas on dermoscopy were the clue to diagnose early lesions. At the borders of these areas, very small, round or triangular structures were found. At the lesion periphery, dermoscopy revealed a fine reticular pattern that helped to identify them as a melanocytic lesion. A progressive increase of the number and size of erased areas was accompanied by the appearance of various angulated structures around them (angulated lines, zig-zag structures or polygonal structures). Analysis of invasive lesions revealed very large erased areas containing white lines and atypical vascularisation. CONCLUSIONS: We have identified the dermoscopic early features and signs of progression by examining the dermoscopic and reflectance confocal microscopy findings of early and invasive extrafacial lentigo maligna.

Fat necrosis and subcutaneous abscesses due to apomorphine / Necrosis grasa y abscesos subcutáneos por apomorfina

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Combined in vivo reflectance confocal microscopy and digital dermoscopy for follow up of patients at high risk of malignant melanoma: A prospective case series study.

Digital dermoscopy (DD) follow up is a useful strategy for monitoring patients at high risk of melanoma. Reflectance confocal microscopy (RCM) is a valuable second-level examination after dermoscopy for the evaluation of difficult to diagnose lesions. The aim of this study was to assess the value of RCM in routine DD monitoring of patients at high risk of melanoma. In this prospective study, performed over 22 months, changing melanocytic lesions were detected by DD and excised. RCM imaging was performed before surgical excision of all the lesions, and histopathology used as the gold standard diagnostic test. Eighty-seven lesions, including 11 thin melanomas, were studied. Dermoscopic evaluation at follow up revealed a significant association between melanoma and asymmetry in two axes (P = 0.035). Enlargement and other changes in structure or color did not significantly differ between nevi and melanomas. Widespread pagetoid cells, non-edged papillae, irregular and dishomogeneous junctional clusters, and sheet-like structures were significantly associated with malignancy (P < 0.001). RCM allowed accurate diagnosis of melanoma in 10 of 11 cases (90.9%). The remaining case was classified as a dysplastic nevus. Forty-six lesions (52.8%) in which RCM revealed no atypia were deemed unnecessarily removed. This study was limited by sample size. In conclusion, combined DD and RCM facilitates the recognition of thin malignant melanomas and reduces unnecessary excisions.